1. Field of the Invention
The present invention relates to a connection structure between an antenna element and a coaxial cable connector, and an antenna apparatus including the connection structure.
2. Description of the Related Art
An antenna apparatus, in which an antenna element is mounted on a mounting plate fixed to an extending end portion of an elongated support whose base portion is fixed to a base, is widely known.
In the antenna apparatus of this kind, a coaxial cable from an antenna control apparatus installed on or outside the base extends from the base portion of the elongated support along the elongated support toward the extending end. And, a coaxial cable connector of the extending end of the coaxial cable is attached to the mounting plate.
A connection terminal of the antenna element and a connection terminal of the coaxial cable connector are electrically connected to each other by connecting both ends of one solid-core conductive line to the connection terminal of the antenna element and the connection terminal of the coaxial cable connector electrically with solder.
The antenna apparatus as described above is used in a DVOR (Doppler VHF Omnidirectional Radio Range) apparatus relating to a radio navigation of aircraft, disclosed in, for example, Japanese Patent Application KOKAI Publication No. 3-267803. The DVOR apparatus includes a disc-shaped radio wave reflection plate which is supported on a base such as a ground or a surface of a building and which is called as a counterpoise, a carrier antenna which is arranged on a center of the radio wave reflection plate, and a plurality of sideband antennas which are arranged on a circle whose center is the carrier antenna on the radio wave reflection plate at equal intervals. The basic structure of each of the sideband antennas is the same as the structure of the above-mentioned antenna apparatus.
Since the DVOR apparatus is installed on out of doors, each of the carrier antenna and sideband antennas is covered with a radome.
When the antenna apparatus which is used out of doors is exposed to strong winds, the elongated support is shook. During this state, the mounting plate which is fixed to the extending end of the elongated support and to which the antenna element is mounted oscillates about the extending end of the elongated support.
When resonance is generated, the oscillation of the extending end of the elongated support becomes large unexpectedly. As a result, unexpectedly repetitive bending is caused in the one solid-core conductive line whose both ends are soldered to the connection terminal of the antenna element and the connection terminal of the coaxial cable connector, and fatigue failure rarely occurs in the one solid-core conductive line.